Nutrition and Exercise Part One: Energy Metabolism

nutrition and exercise

It’s the most wonderful time of the year! MARCH MADNESS!

To go along with the madness, I’m going to start a series of posts all pertaining to one broad topic: Nutrition and Exercise. There is so much information that we can discuss on this subject so I’m splitting it up into a few mini posts so I can make sure that I cover everything thoroughly.

Did you know there are different kinds of exercise? and that these different types of exercise are fueled differently?

It is important for you to understand how to fuel your body before, during and after your workouts. Did you know there was such a thing called a Sweat Ratio? That’s right. You can determine how much water you absolutely need to hydrate your body during a workout.

I’ll have an entire post on ergogenic aids/supplements to help you better understand the labeling and usage of these.

One word: Protein. We will talk about why everyone is so obsessed with protein when it comes to exercising, and I’ll help you figure out exactly how much you should be consuming per day. We will review ways to add lean protein to your meals and snacks.

That’s a lot of information! Let’s start at the beginning:


What is it? Scientifically speaking, energy metabolism is the process of generating Adenosine Triphosphate (ATP) from nutrients. Is high school biology starting to come back into your minds? ATP is considered to be the currency for energy (kind of like how dollars represent our currency). So energy metabolism is creating energy by burning nutrients in your body. Make sense?


Energy metabolism is a GOOD thing but is heavily influenced by multiple other factors.

  • Exercise intensity
  • Exercise duration
  • Frequency of workout
  • Type of activity
  • Gender of individual
  • Fitness level of individual
  • Prior nutrient intake
  • Energy stores

The goal is to increase your energy metabolism, right? So if you look at the list above, all but 1 of the factors are influenced by YOU. The old saying “you get what you give” is very appropriate here. The more you exercise, the higher your energy metabolism rate is. Easy as that.

Types of Exercise/Energy Metabolism

Two types: Aerobic and Anaerobic. Basic terms: with or without oxygen. Again, high school biology really IS useful! High school history, not really. (Mr. Parks, I hated your history class. Sorry for not being sorry.)

Don’t let this next graphic scare you. It has some science-y words but it is helpful to understand what kind of energy is metabolized during the two different types of exercise

energy metabolismLet’s Break this down

Aerobic Energy Systems (aka Cardio)

  • USES oxygen (hence the term Oxidative Pathway)
  • Uses carbohydrates, fat and proteins
  • can be used “indefinitely”
  • Per every 1 glucose molecule used – it can create 39 ATP! (that’s a lot, and that’s good!)
    • Glucose –> CO2 + H2O + 39 ATP (energy)
  • Aerobic energy systems kick in when you are exercising longer than 2-3 minutes
    • running/jogging, swimming, cycling, aerobics, basketball, soccer, etc
  • Once you start breathing heavier (oxygen is readily available in your muscles) the body will switch from anaerobic to aerobic energy systems. Our bodies are SO smart

BASIC TERMS: Aerobic energy systems create a LOT of energy. The KREBS CYCLE and the Electron Transport Chain are real people! You can tell when you are using aerobic energy quite easily. Are you breathing heavily? then, Yes! Aerobic exercises are your best bet when wanting to lose weight and have all kinds of health benefits – like decreasing your risk for heart disease, diabetes, stroke….the list goes on.

krebs cycle

Anaerobic Energy Systems (aka resistance training)

  • NO oxygen used
  • Uses mostly carbohydrates  and lasts up to 2-3 minutes
  • Phosphagen System
    • ATP (energy that is readily available in the muscle) is not sufficient to provide continuous supply of energy
    • Used during 10 seconds of high intensity (jerk in weightlifting, fast break in basketball
  • Glycolytic Pathway
    • Uses stored carbohydrates (glycogen) in muscles, which then creates lactic acid which causes muscle fatigue – the reason you can’t do anaerobic exercise for long periods of time
    • Supports events lasting 60-180 seconds (sprints or resistance exercise bout)

BASIC TERMS: Anaerobic energy systems are used usually when weight lifting, yoga or doing non-cardio exercise. Once your heart rate increases or your breathing starts to intensify, aerobic kicks in. This is important for toning, decreasing stored fat cells, muscle growth and overall body strengthing.

Are you asking yourself, WHY DOES THIS MATTER?

I believe it’s important to know what kind of effects your exercise has on your body – on a cellular level. It’s important to know that energy generated by anaerobic metabolism is 1/10 less than aerobic. But don’t let your mind trick you into thinking that anaerobic exercise isn’t as good. Some people complain about their “plateau” of workout progression. While their cardio health is probably great, overtime aerobic exercise results can even out. If this is the case for you, try adding in some anaerobic resistance training to your workout and watch your body transform. Replacing stored fat cells with lean muscle mass is a great benefit for oxygen-less workouts. The same for vice-versa. Adding in some aerobic activity to your daily weight lifting routine will make your heart stronger, among other things.

Aerobic exercise increases your endurance and cardiac health while anaerobic exercise will not only help you burn fat but also help you gain lean muscle mass. So the important takeaway message is – DO BOTH!

Try the HITT workouts I wrote about last month – I LOVE them.

I hope this post didn’t confuse you too much. As always, I’m available for questions anytime. Please email me at or comment on our facebook page with questions or reader requests.

Up next: Pre-workout Nutrition

Oh, and GO CATS! 🏀